This dissertation marries multiple genres of historical inquiry, and draws upon underappreciated academic insights from Japan, China, and Taiwan to consider two questions. First, how the 'professional' Chinese diplomat, fluent in the sociocultural expectations of Western European diplomacy, emerged in the early twentieth century from a country whose various dynasties had, for two millennia, led and participated in an entirely distinct diplomatic culture of its own. And second, how a group of non-Chinese intermediaries working in China's first modern diplomatic institutions helped nurture this transformation. The story it tells sits at the intersection between Chinese, diplomatic, and transnational history. However, its methodology is decidedly interdisciplinary: it is one of the first studies of modern Chinese diplomatic history to draw upon the 'New Diplomatic History', a pioneering approach that moves beyond the field's traditional focus on the high politics of state-to-state level interactions, to interrogate the overlooked actors, sites, circuitries and processes of diplomatic interaction using insights from sociology, literary theory, and network analysis. Today, the 'Chinese diplomat' has become synonymous with the invective-hurling 'Wolf Warrior' diplomats that embody the aggressive and normatively out-of-kilter diplomacy of the People's Republic of China. However, recent scholarship emerging from Japan, China and Taiwan has demonstrated that by the 1910s, Qing China (1644-1912) had cultivated a competent corps of professional diplomats who could perform confidently on the international stage, and who-unlike their 'Wolf Warrior' successors-fully embraced Western European diplomacy's normative prescriptions for diplomatic conduct and practice. For the Qing, the sociocultural, linguistic, and pragmatic chasms that had to be crossed to achieve this engagement with Western diplomatic culture constituted a remarkable feat of socialisation. From the first century AD until 1895, China had led its own distinct diplomatic culture. In this China-focused international order, 'tributary' states such as Korea and Vietnam subscribed ideologically to a hierarchical order in which the primacy of Chinese civilisation and the mandate of the Chinese emperor to rule all sublunary things were given articulation through a variety of rituals and cultural practices. However, in the mid-nineteenth century, foreign encroachment upon China compelled the dynasty to develop a framework for engaging with states on equal terms and according to the normative prescriptions of Western European diplomatic culture. At its core, this dissertation asks the question of 'how, by the early twentieth century, did Qing China achieve normative mastery of Western European diplomatic practice and culture, and in the process, produce a corps of professional diplomats whose expertise and experience would feed into and fuel later Chinese diplomacy?'. The pioneering Japanese- and Chinese-language scholarship alluded to above has, to date, only considered this process from the perspectives of Qing diplomats' receptivity to international law and institutional shifts. However, to be a 'professional' diplomat in the late nineteenth and early twentieth centuries was to possess sociocultural fluency in manners and etiquette, to display oratorical and rhetorical distinction in European languages, to dissimulate where appropriate, and to have cultivated the pragmatism to bring these skills to bear, where appropriate, for accessing networks of knowledge and power. Indeed, to be 'one of them' was not just about possessing specialist knowledge of international law, but rather about the ability to recognise and perform sociocultural nuances that were either reified as ambassadorial ideals in diplomatic handbooks, or, in many cases, just expected implicitly. This dissertation interrogates how this metamorphosis was articulated in the everyday tools and circuitry of Qing diplomatic practice, including the art of negotiation, the crafting of rhetoric in specialised linguistic registers, and the deployment of the press. In doing this, however, this study employs a novel methodological lens. It interrogates the shifting roles of subministerial foreign actors working within Qing China's legations as interpreters, secretaries, counsellors, and legal advisers. An interrogation of the foreign presence working within China's legations may seem like a bizarre way of addressing the research question outlined above. Why not just look at how China's diplomats themselves were operating? This methodology in fact derives from Qing approaches to diplomatic practice in the period under question. Initially, foreigners were employed in the Qing's legations to perform tasks that the Qing diplomats and their staff themselves could not, or did not want, to do. Indeed, at least initially, any form of profound engagement with 'Western affairs'-of which diplomacy constituted a sub-genre-was anathema to the Confucian scholar-officials who piloted these new overseas institutions in a ministerial capacity. This was indicative of the ideological milieu that the Qing bureaucrats were socialised into: to engage at any level of profundity with a non-Chinese civilisation was to engage in barbarism. What's more, these Qing officials had not arrived at their overseas posts as 'diplomats' replete with training in the morass of implicit customs and practices that undergirded Western European diplomacy; they were learning as they went along. Given such circumstances, the work delegated to and performed by these foreigners, and the evolution of the content of this work, provides a unique space from which we can derive new insights about the nature of the Qing's interaction with Western European diplomatic practice and culture. This novel methodological approach has proven to be highly effective. Drawing on multilingual archival sources collected in America, Britain, France, Japan, and Taiwan, this study reveals that while these foreigners were first employed by the Qing in the late 1870s to handle cultural explication, interpretation and clerical work, their roles were fundamentally transformed in the 1880s. From this period, they came to exert a leading influence on Qing diplomacy as rhetoricians, orators, negotiators, press officers, networkers and strategists. I argue that this transformation was indicative of a rapid macro-level transformation in the Qing's engagement with Western European diplomatic practice and culture, in that their use of foreigners in this way demonstrated, among other things, a desire to persuade their diplomatic interlocutors that they were a competent diplomatic entity who ought to be taken seriously. In the early twentieth century, however, a shift towards the dismantling of this foreign presence and the extent of its involvement in Chinese diplomacy could be observed. This new phase in the evolution of Chinese diplomatic practice, I argue, can broadly be understood as indicative of the emergence of the professional Chinese diplomat. Indeed, having now come to conceive of itself in Western terms as a sovereign nation-state, China identified diplomacy, in the Western sense, as an indispensable component of statecraft that ought to be overseen and run on a day-to-day basis by Chinese actors. At the same time, this study reveals that the foreigners who worked in the Qing's legations were not mere middlemen. Their craft involved the transposing of complex levels of nuance from one party to the other and the reformatting of Qing views as culturally commensurable ideas that their foreign interlocutors could understand. At times, they even engaged in their own private diplomatic interventions that aimed to bring about a fairer outcome for the Qing. Their work also provided an inadvertent or, at times, deliberate, model for their Qing colleagues on the execution of specific nuances of diplomatic practice. In other words, their significance goes far beyond their utility as a methodological device. They, too, were critical contributors to the Qing diplomatic metamorphosis.